Beook



` N0.31Z,538. u

(NO OSIJ.

C. s. WESTBROQK.

ROCK DRILL. v

Patented Feb. 17, 1885.,

NIEUW ATTORNEYSA N. PETERS. Fhcxo-Lilhogmpher, wasni nnnnnnnnn c.

UNITED STATES PATENT OFFICE.

CHARLES S.ESTBROOK, OF SPRAGUEVILLE, NEV YORK.

ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 312,538, dated February17, 1.885.

y Application filed June 1G. 1884. (No model To @ZZ whom it mayconcern,.-

Be it known that I, CHARLES S. Wnsr- BROOK, a citizen of the UnitedStates, and a resident of Spragueville, in the county of St. Lawrenceand State of New York, have invented certain new and useful Improvementsin Rock-Drills; and I do hereby declare that the following is a full,clear, and exact description of the invention, which will enable othersskilled in the art to'which it appertains to make and use the same,reference being had to the accompanying drawings, which form a part ofthis specification.

My invention relates to that class of cylinders known as valvelesscylinders, and more particularly to the form of the piston to thecylinder, and to the ports and channels in the cylinder, by which whenactuated by suitable power the reciprocating motion of the piston letsin and cuts off theimpelling medium and opens and closes theeXhaustports without the a-id of valves.

The object of my invention is to afford a simple and compact apparatusfor obtaining motivel power and force from steam, compressed air, gas,or other kind of vapor, for use in all classes of engines in which ashort rapid forwardv stroke of the piston is desirable. rlhe object isaccomplished by making the cylinder, ports, and piston in the fornishown in the accompanying drawings, which represent the inventionapplied to -a rockdrll, and in whch- Figure lis a longitudinal sectionalview. Fig. 2 is a similar view at right angles to the former View. Figs.3, 4, and 5 are cross-sections on the'lines x x, y y, and z z, Fig. 1.

Similar letters refer to similar parts throughout the several views.

A is a metal cylinder of ordinary construction. In the present case,where the invention is applied to a rock-drill, one head of thiscylinder is provided with a stuffing-box, B, Fig. l, of suitableconstruction, through which the piston-rod (here the drill-shaft)passes, while through the other cylinder-head is passed thesteep-threaded screw and ratchet C, usual in rock-drills, forgiving therequired turn to the piston and drill. In practice any other suitabledevice may be substituted therefor, and where the cylinder is used inany other form of motor, except in the case of a steamhammer, the steepscrew and ratchet will be dispensed with and the piston-rod will workthrough stuffing-boxes at either or both ends of the cylinder, as may befound convenient. The impelling mediumis supplied to the cylinderthrough the inlet D, which may be of any suitable material anddimensions, opening into the cylindrical side walls of the cylinder A,as shown in Fig. l. The position of the supply-pipe will be determinedby the character of the stroke which the piston is designed to make. lnFig. 1 thesupply-pipeis so placed that a line drawn verticallythroughits center will intersect the central pointof the line representing thedistance traversed by the piston. It will vary in position according asthestroke of the piston is designed to be slower than the other, ashereinafter specified.

In my invention the piston I is made substantially in the form shown inFig. l, with the annular groove .or recess k at its center. In practicethe piston is cast in one solid piece, of any suitable metal, and turneddown in the central position of its cylindrical surface K, so that itsdiameter there shall be less than at its extremities, as seeninFig. 4.The

length of the piston will Vary according to the length of the stroke,size of cylinder, Src.

F and G are two feed-ports cut in the interior side walls and at eitherend of the cylinder, as shown in Fig. l, in any convenient longitudinalvertical plane, but preferably in that which intersects the center ofthe inletpipe D, as shown in the views.

For the purpose of diminishing the friction caused by the impellingmedium entering the cylinder, a recess, E, is formed in the inner sidewalls of the cylinder around the inletpipe D, as shown,at the pointwhere it enters. The ports F and G are placed at an equal distance fromthe recess, and are separated therefrom by shoulders or bridgesHH. Theports open into the channels or ducts I, which open through the sides ofthe cylinder into the same at both ends through ports K and L, and theports and duct and channel leadingtothe rear end of the cylinder, whichis indicated by L, are preferably of larger diameter and capacity thanthe ports and channel leading to theforward end of the same.

O O are the exhaust-ports, of any convenient ICU size and shape, whichmay be placed at any point in the side walls where they will beuncovered by the two piston-heads alternately` at the end of eachstroke. I prefer, however7 to place them,assl1own in Figs. 1 and 2,inthe Vertical plane of the feed-ports.-

The operation of the cylinder and piston is substantially similar to theoperation of the cylinder and piston shown and described in myapplication for Letters Patent for another rockdrill led this day in thePatent Office. The impelling medium entersthrough the inlet-port fromwhich it is conveyed by the recess in the piston to one' of the innerportsof the channels, through that channel to the end of the cylinder,where it acts upon the piston, which, in progressing, will cut off theimpelling medium, allowing what is left behind it to work byitsexpansion until the piston uncovers the exhaust-port, when the recess inthe piston will connect the inlet-recess with the other channel, causingthe piston to return, &c.

I am aware that many attempts have been made to construct a cylinder ofthis character for use in rock-drills, steam-hammers, &e.; but that nonehave hitherto been invented which have worked successfully. I find,however, that when the feed-ports are so arranged that a greater amountof impelling medium will be supplied to the piston upon the forwardstroke than upon the backward stroke, and when the arrangement anddisposition of the piston are such that the supply of inipelling mediumwill be cut off at an earlier moment upon the backward stroke than uponthe forl ward stroke, the diiiiculties heretofore experienced in allvalveless cylinders, and particularly when 'they are applied toroek'drills, will practically cease to exist. These difficultiesconsist, chiefly, in starting the piston on the return or upward stroke.

By the arrangement of parts heretofore described I am able to leave asmall amount of impelling medium in the forward end of the cylinder atthe end of the forward stroke, which will be compressed by the blow orstroke of the piston, and enable it to rebound and enter upon its upwardor backward stroke, even before the direct supply commences to operateupon the piston.

I claim as my inventionl. In a valveless cylinder for use in rockdrills,stea1n-ha1nmers, and other forms of engines, the hereinbefore-describedcombination, consisting ofthe cylinder, the inlet-port formed into arecess in the inner wall of the cylinder, the feed-ports consisting'ofchannels in the sidewalls of the cylinder the extremities of which openinto its hollow interior at either end and on either side of the inletand are separated therefrom by shoulders or bridges, the feed-port andchannel at the rear end of Said cylinder being of larger dimensions and0f greater carrying capacity than the forward P01-tand channel, and theexhaust-ports in the side walls of said cylinder.

2. In a valveless cylinder for use in rockdrills, steam-hammers, pumps,Ste., the hereinbefore-described arrangement of the cylinder ports andpiston, whereby a portion ofthe impelling medium will be admitted intothe forward or lower end of the cylinder before the end of the forwardor downward stroke ot' the piston, for the purposes set forth.

In testimony that l claim the foregoing as my own I have hereuntoafiixed my signature in presence of two witnesses.

CHARLES S. VESTBROOK.

Vitnes'ses:

J. 0. SHnLDoN, I-I. XV. SUDDs.

